This invention is related to a device for reciprocably swinging an infant in a pendulum motion, which motion is supplied by a solenoid-actuated power arm. The infant is placed in an infant-support means ("seat") which is supported by elongated struts ("hangers"). The assembly of seat and hangers comprises an infant-swinging means which may be a "rocking cradle" or swing (either of which are hereafter referred to as "swing" for brevity).
It is known that oscillatory motion is routinely supplied for numerous operations by electrically powered solenoid means with appropriate switching means. However, the precise manner in which reciprocation provided by a solenoid means may be effectively translated to desirable reciprocatory motion of an automatic swing, yet maintaining proper timing, is far from clear, for numerous reasons.
Heretofore, the power requirements for reciprocating a swing have dictated electric motor-driven, or mechanically actuated means for providing the swinging motion (oscillatory movement) of the swing, and the devices became expensive to manufacture. Such electric motor-driven swings are disclosed in U.S. Pat. Nos. 3,031,687 and 3,146,985; a spring-powered motor is disclosed in U.S. Pat. No. 3,371,358. Again, because of the relatively high power required to keep a swing swinging, electromagnetic coils have been energized to exert a magnetic pull on an armature during each oscillation, which pull compensates for and overcomes the loss of momentum as the swing falls through one portion of its arc (the "down" arc) and continues into the other portion of its arc (the "up" arc). Typical of such devices are those described in U.S. Pat. Nos. 3,261,032 and 3,883,136.
A specially designed solenoid-driven swing is disclosed in U.S. Pat. No. 3,842,450, but its power requirements are such that it is inoperable except with a main electric supply.
Though, theoretically, the cost of a power-operated swing for an infant bears only ever so slightly on considerations of what structural features may be combined to provide the desired reciprocatory motion, the simple fact remains that cost is the first of two all-important considerations which determine the marketability of such a device. The second consideration is safety.
It is unnecessary to dwell upon the heightened safety-consciousness of the child-rearing public whose proper concern is voiced by various governmental agencies striving to provide child-safe devices for the benefit of young children unable to weigh or act upon such considerations themselves. This is especially true for infants up to about two (2) years old who weigh about 20 lb (pounds). It is equally unncessary to discuss the possible hazards associated with power-operated children's playthings and artifacts, particularly swings, which require that they be direct-main-powered, that is, connected to electric mains carrying 110 volts or more, and conventionally fused at a minimum of 10 amps, so that danger is within easy reach of the infant. It is therefore not surprising that, to my knowledge, no electrically-powered infant's swing has been successfully marketed. The problem has been to provide an inexpensive swing which can be battery-operated with either an inexpensive, commercially available disposable alkaline battery, or a rechargeable sealed lead-acid or nickel-cadmium battery, or a D-C adapter (transformer) which is a source of current, all of which provide current at a voltage no more than about 24 volts, preferably 3 or 4 volts, and at low amperage. Where a rechargeable battery is used, it should provide operation of the swing for several hours before it requires recharging. The demand of the marketplace has been for a child-safe swing which will operate reliably and relatively long, yet be reasonably sale-priced. All solutions proffered to date have inevitably provided operational unreliability italicized by the necessity to provide high quality components at low cost. This invention fulfills the long-felt need for a highly marketable, child-safe and reliable device which will operate for several hours continuously even on a commercially available rechargeable battery, requiring only that the oscillatory movement of the swing be initiated manually when the infant is placed in the seat.